Plz help diagnose cylinder misfire and wet spark plug..

[Dnutt]

So about a month ago my coil pack went bad so I replaced it. (#8). Also checked plugs and they looked fine. The other day I got the code again misfire #8 so I replaced the coil again even though it's running fine. But 1 spark plug was wet with either oil or coolant so I replaced both. Reset code but it throws it again within 5 min of driving. Why would only 1 plug be wet? Any ideas on what's wrong?
2019 5.7 188k miles

 

[kapinallinen2]

So about a month ago my coil pack went bad so I replaced it. (#8). Also checked plugs and they looked fine. The other day I got the code again misfire #8 so I replaced the coil again even though it's running fine. But 1 spark plug was wet with either oil or coolant so I replaced both. Reset code but it throws it again within 5 min of driving. Why would only 1 plug be wet? Any ideas on what's wrong?
2019 5.7 188k miles View attachment 170668

That looks pretty good, what does the wet one look like?
edit: a failing injector could also cause a misfire.

 

[Dnutt]

That looks pretty good, what does the wet one look like?
edit: a failing injector could also cause a misfire.

That is the wet plug. The other plug was perfectly dry and normal color

 

[kapinallinen2]

That is the wet plug. The other plug was perfectly dry and normal color

You must be referring to the oil on the threads, my guess is that the valve cover gasket is leaking some oil into the plug well.
With your mileage, would not worry about it too much and that will not cause a misfire.
Look into a failing fuel injector being the culprit.
Run some Lucas injector cleaner for couple tank fulls, might just clear the misfire problem.

 

[6of36]

Recently I came across info, that there are now counterfeit spark plugs out on the market. Inferior quality. Causing misfires. The oil on the plug, looks like you have a leaky tube in your valve cover.

 

[HSKR R/T]

So about a month ago my coil pack went bad so I replaced it. (#8). Also checked plugs and they looked fine. The other day I got the code again misfire #8 so I replaced the coil again even though it's running fine. But 1 spark plug was wet with either oil or coolant so I replaced both. Reset code but it throws it again within 5 min of driving. Why would only 1 plug be wet? Any ideas on what's wrong?
2019 5.7 188k miles View attachment 170668

There's more to a misfire code than spark. Always want to diagnose before replacing parts. Good chance the coil was fine. There is quite a bit of build up in that plug. Personally, if I pulled that out of my engine, I'd probably go ahead and replace all 16 spark plugs.

 

[Dnutt]

There's more to a misfire code than spark. Always want to diagnose before replacing parts. Good chance the coil was fine. There is quite a bit of build up in that plug. Personally, if I pulled that out of my engine, I'd probably go ahead and replace all 16 spark plugs.

I would agree but that plug looked completely fine 1 month ago. The other plug for that cylinder also looks fine...

 

[scully]

Try moving both plugs from the misfiring cyc to another cyc and clear your code and drive , see if the misfire "followed " or not .....then you will at least have a starting point

 

[HSKR R/T]

I would agree but that plug looked completely fine 1 month ago. The other plug for that cylinder also looks fine...

Modern PCMs are a little better, but I've found that sometimes the cylinder called out for misfire isn't the actual cylinder with an issue.

Another thing, does your engine have the Hemi tick? Or a loud tick/knock? I swapped spark plugs in a buddies truck who thought that's where his misfire was coming from. I hadn't heard the truck run myself. After replacing the spark plugs and he fired it up, I knew immediately his spark plugs weren't the issue. He had a lifter fail. Now he's getting a new engine for the tune of $5k.

 

[Dnutt]

Modern PCMs are a little better, but I've found that sometimes the cylinder called out for misfire isn't the actual cylinder with an issue.

Another thing, does your engine have the Hemi tick? Or a loud tick/knock? I swapped spark plugs in a buddies truck who thought that's where his misfire was coming from. I hadn't heard the truck run myself. After replacing the spark plugs and he fired it up, I knew immediately his spark plugs weren't the issue. He had a lifter fail. Now he's getting a new engine for the tune of $5k.

It has a very faint tick but honestly it sounds like all the other hemis I've had